This invention relates to a multiply-complexed one-dimensional structure, multiply-twisted helix, multiply-looped ring structure and functional material, especially suitable for use as highly functional materials based on a novel principle.
For application of a solid material to electronic or optical devices, physical properties of the material may restrict its applications. For example, in case of using a semiconductor material in a light emitting device, it will be usable in a device of an emission wavelength corresponding to the band gap of the material, but some consideration will be necessary for changing the emission wavelength. Regarding physical properties related to semiconductor bands, controls by superlattices have been realized. More specifically, by changing the period of a superlattice, the bandwidth of its subband can be controlled to design an emission wavelength.
Targeting on controlling many-electron-state structures by material designs, the Inventor proposed many-body effect engineering by quantum dot-bonded structures and has continued theoretical analyses ((1) U.S. Pat. No. 5,430,309; (2) U.S. Pat. No. 5,663,571; (3) U.S. Pat. No. 5,719,407; (4) U.S. Pat. No. 5,828,090; (5) U.S. Pat. No. 5,831,294; (6) J. Appl. Phys. 76, 2833(1994); (7) Phys. Rev. B51, 10714(1995); (8) Phys. Rev. B51, 11136(1995); (9) J. Appl. Phys. 77, 5509(1995); (10) Phys. Rev. B53, 6963(1996); (11) Phys. Rev. B53, 10141(1996); (12) Appl. Phys. Lett. 68, 2657(1996); (13) J. Appl. Phys. 80, 3893(1996); (14) J. Phys. Soc. Jpn. 65, 3952(1996); (15) Jpn. J. Appl. Phys. 36, 638(1997); (16) J. Phys. Soc. Jpn. 66, 425(1997); (17) J. Appl. Phys. 81, 2693 (1997); (18) Physica (Amsterdam) 229B, 146(1997); (19) Physica (Amsterdam) 237A, 220(1997); (20) Surf. Sci. 375, 403(1997); (21) Physica (Amsterdam) 240B, 116(1997); (22) Physica (Amsterdam) 240B, 128(1997); (23) Physica (Amsterdam) IE, 226(1997); (24) Phys. Rev. Lett. 80, 572(1998); (25) Jpn. J. Appl. Phys. 37, 863(1998); (26) Physica (Amsterdam) 245B, 311(1998); (27) Physica (Amsterdam) 235B, 96(1998); (28) Phys. Rev. B59, 4952(1999); (29) Surf. Sci. 432, 1(1999); (30) International Journal of Modern Physics B. Vol. 13, No. 21, 22, pp.2689-2703, 1999). For example, realization of various correlated electronic systems is expected by adjusting a tunneling phenomenon between quantum dots and interaction between electrons in quantum dots. Let the tunneling transfer between adjacent quantum dots be written as t. Then, if quantum dots are aligned in form of a tetragonal lattice, the bandwidth of one electron state is Teff=4t. If quantum dots form a one-dimensional chain, the bandwidth of one electron state is Teff=2t. In case of a three-dimensional quantum dot array, Teff=6t. That is, if D is the dimension of a quantum dot array, the bandwidth of one electron state has been Teff=2Dt. Here is made a review about half-filled (one electron per each quantum dot) Mott transition (also called Mott-Hubbard transition or Mott metal-insulator transition). Let the effective interaction of electrons within a quantum dot be written as Ueff, then the Hubbard gap on the part of the Mott insulator is substantially described as xcex94=Ueffxe2x88x92Teff, and the Mott transition can be controlled by changing Ueff or t. As already proposed, the Mott-Hubbard transition can be controlled by adjusting Ueff or t, using a field effect, and it is applicable to field effect devices (Literatures (5), (6), (11) and (14) introduced above).
On the other hand, reviewing the equation of xcex94=Ueffxe2x88x92Teffxe2x88x922Dt, it will be possible to control Mott-Hubbard transition by controlling the dimensionality D of-the system. For this purpose, the Applicant already proposed a fractal-bonded structure that can continuously change the dimensionality, and have exhibited that Mott-Hubbard transition is controllable by changing the fractal dimensions.
To enable designing of wider materials, it is desired to modify and control the dimension of materials by methods different from the fractal theory. For example, for the purpose of changing the nature of phase transition, it is first conceivable to control the number of nearest-neighbor elements among elements ago forming a material.
On the other hand, here is changed the attention to ferromagnetic phase transition taking place in the fractal-bonded structure. Of course, ferromagnetic materials are one of the most important magnetic storage materials. When using z as the number of nearest-neighbor atoms, kB as the Boltzmann constant, T as temperature, it is known that spontaneous magnetization M in the averaging theory describing ferromagnetic phase transition satisfies
M=Tanh(zM/kBT)
The highest among temperatures T leading to solutions of Mxe2x89xa00 of this equation is the critical temperature Tc. As readily understood from the equation, Tc is proportional to z. When assuming a tetragonal lattice, since z=2D, it is expected that the critical temperature of ferromagnetic phase transition depends on the dimensionality of a material. The Inventor executed more exact Monte Carlo simulation, and showed that the critical temperature of ferromagnetic transition occurring in a fractal-bonded structure could be controlled by the fractal dimensions.
It is therefore an object of the invention to provide a multiply-twisted helix complementary with a fractal-shaped material and representing a new physical property, and a functional material using the multiply-twisted helix.
A further object of the invention is to provide a multiply-looped ring structure complementary with a fractal-shaped material and representing a new physical property, and a functional material using the multiply-looped ring structure.
A still further object of the invention is to provide a multiply-complexed one-dimensional structure complementary with a fractal-shaped material and representing a new physical property, and a functional material using the multiply-complexed one-dimensional structure.
The Inventor proposes a multiply-twisted helix as one of spatial filler structures. This is made by winding a spiral on a spiral structure as a base like a chromatin structure that a gene represents, and by repeating it to progressively fill a three-dimensional space. By adjusting the spiral pitch, the spatial filling ratio can be selected, and dimensionality of a material, i.e. the number of nearest-neighbor elements in this structure can be modified.
In other words, here is proposed a multiply-twisted helix in which spirals are made up by using a spiral structure as the base and using the spiral structure as an element. In this structure including hierarchically formed multiple spirals, one-dimensional vacancies penetrate the structure to form a structure as a porous material. However, by adjusting the turn pitch of the spirals, the number of nearest-neighbor elements can be changed. According to researches by the Inventor, the value of critical inter-electron interaction of Mott-Hubbard metal-insulator transition in this kind of structure can be controlled by the spiral pitch.
The multiply-twisted helical structure may be formed regularly; however, in case a multiply-twisted helical structure is actually made, bonding positions appearing among spiral layers possibly distribute randomly. The degree of the randomness can be new freedom of material designs. Taking it into consideration, for the purpose of clarifying the effect of the random distribution, exact simulation was conducted. As a result, introduction of randomness has been proved to increase the width of the Mott-Hubbard gap and enhance the Mott insulation. Therefore, the value of critical inter-electron interaction of Mott-Hubbard metal-insulator transition can be controlled not only by controlling the degree of randomness of the spiral turn pitch but also by controlling the degree of randomness regarding inter-layer bonding positions.
Still in the multiply-twisted helix, there is also the inter-layer bonding position as a control parameter, in addition to the degree of randomness regarding the spiral turn pitch and inter-layer bonding positions. That is, by controlling inter-layer bonding positions, desired material designs are possible. More specifically, freedom of parallel movements of inter-layer bonding, that is in other words, simultaneous parallel movements of inter-layer bonding positions, can be used to control the value of critical inter-electron interaction of Mott-Hubbard metal-insulator transition occurring in the structure.
The multiply-twisted helix can be used as a magnetic material as well. That is, in the multiply-twisted helix, the critical temperature for ferromagnetic phase transition to occur can be controlled by adjusting the turn pitch.
The inventor also proposes a multiply-looped ring structure as another spatial filler structure, which is different in structure from the multiply-twisted helix but similar in effect to same. This can be obtained by hierarchically forming rings, using a ring as a base. The number of nearest-neighbor elements can be changed progressively by adjusting the number of elements of low-order rings forming high-order hierarchies. Thereby, the spatial filling ratio can be established, and the dimensionality of the material can be modified. In this multiply-looped ring structure, the above discussion is directly applicable only if the turn pitch in the multiply-twisted helix is replaced by the number of elements.
The inventor further proposes a multiply-complexed one-dimensional structure as a more general (TIE spatial filler structure that includes both a multiply-twisted helix-and a multiply-looped ring structure.
This is obtained by hierarchically forming one-dimensional structure systems having a finite curvature using a one-dimensional structure system having a finite curvature as the base. In this case, the number of nearest-neighbor elements can be changed progressively by adjusting the curvature of low-order one-dimensional structure systems forming high-order hierarchies. Thereby, the spatial filling ratio can be established, and the dimensionality of the material can be modified. In this multiply-complexed one-dimensional structure, the above discussion is directly applicable only if the turn pitch in the foregoing multiply-twisted helix or the number of elements in the foregoing multiply-looped ring structure is replaced by the curvature. In this multiply-complexed one-dimensional structure, those having a finite twisting ratio correspond to multiply-twisted helixes whilst those having zero twisting ratios correspond to multiply-looped ring structures.
The present invention has been made as a result of progressive studies based on the above review.
That is, to overcome the above-indicated problems, according to the first aspect of the invention, there is provided a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of a thinner one-dimensional structure having a finite curvature, comprising:
at least two layers of the one-dimensional structures bonded to each other in at least one site.
According to the second aspect of the invention, there is provided a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of a thinner one-dimensional structure having a finite curvature, characterized in:
exhibiting a nature regulated by setting a curvature in case the one-dimensional structure is made of thinner one-dimensional structures.
According to the third aspect of the invention, there is provided a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of a thinner one-dimensional structure having a finite curvature, characterized in:
having a dimensionality regulated by setting a curvature in case the one-dimensional structure is made of thinner one-dimensional structures
According to the fourth aspect of the invention, there is provided a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of a thinner one-dimensional structure having a finite curvature, having a random potential introduced therein, and at least two one-dimensional structures bonded in at least one site, characterized in:
a quantum chaos occurring therein being controlled by setting the intensity of the random potential, by setting the intensity of layer-to-layer bonding, by setting the curvature used when forming the one-dimensional structure from thinner one-dimensional structures, or by adding a magnetic impurity.
Control of the quantum chaos produced typically relies on setting a bonding force between layers. Addition of magnetic impurities contributes to a decrease of the bonding force between layers and good control of the quantum chaos.
According to the fifth aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of thinner one-dimensional structures having a finite curvature, characterized in:
at least two layers of the one-dimensional structures being bonded to each other in at least one site.
According to the sixth aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of thinner one-dimensional structures having a finite curvature, characterized in:
the multiply-complexed one-dimensional structure exhibiting a nature regulated by setting the curvature used when the one-dimensional structure is made of thinner one-dimensional structures.
According to the seventh aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-complexed one-dimensional structure having a hierarchical structure in which a linear structure as an element of a one-dimensional structure having a finite curvature is made of thinner one-dimensional structures having a finite curvature, characterized in:
the multiply-complexed one-dimensional structure having a dimensionality regulated by setting a curvature in case the one-dimensional structure is made of thinner one-dimensional structures.
According to the eighth aspect of the invention, there is provided a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of thinner spiral structures, characterized in:
at least two layers of spiral structures being bonded in at least one site.
According to the ninth aspect of the invention, there is provided a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of thinner spiral structures, characterized in:
exhibiting a nature regulated by setting a turn pitch in case the spiral structure is made of thinner spiral structures.
According to the tenth aspect of the invention, there is provided a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of thinner spiral structures, characterized in:
having a dimensionality regulated by setting a turn pitch in case the spiral structure is made of thinner spiral structures.
According to the eleventh aspect of the invention, there is provided a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of a thinner spiral structure, having a random potential introduced therein, and at least two spiral structures bonded in at least one site, characterized in:
a quantum chaos occurring therein being controlled by setting the intensity of the random potential, by setting the intensity of layer-to-layer bonding, by setting the turn pitch used when forming the spiral structure from thinner spiral structures, or by adding a magnetic impurity.
Control of the quantum chaos produced typically relies on setting a bonding force between layers. Addition of magnetic impurities contributes to good control of the quantum chaos. Decreasing the bonding force between layers also contributes to good control of the quantum chaos.
According to the twelfth aspect of the invention, there is provided a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of a thinner spiral structure, and having at least two layers of spiral structures bonded in at least one site, characterized in:
the bonding performance between linear structures as elements of the spiral structure being controlled by a turn pitch in case of forming the spiral structure from thinner spiral structures, by the bonding force between the layers, or by a fluctuation in the bonding site between at least two layers of spiral structures.
According to the thirteenth aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of thinner spiral structures, characterized in:
at least two layers of spiral structures in the multiply-twisted helix being bonded in at least one site.
According to the fourteenth aspect of the invention, there is provided a functional material including in at least a part thereof a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of thinner spiral structures, characterized in:
the multiply-twisted helix exhibiting a nature regulated by setting a turn pitch produced when the spiral structure is made of thinner spiral structures.
According to the fifteenth aspect of the invention, there is provided a functional material including in at least a part thereof a multiply-twisted helix having a hierarchical structure in which a linear structure as an element of a spiral structure is made of thinner spiral structures, characterized in:
the multiply-twisted helix having a dimensionality regulated by setting a turn pitch in case the spiral structure is made of thinner spiral structures.
According to the sixteenth aspect of the invention, there is provided a multiply-looped ring structure having a hierarchical structure in which an annular structure as an element of a ring structure is made of a thinner ring structure, characterized in:
at least two layers of ring structures being bonded in at least one site.
According to the seventeenth aspect of the invention, there is provided a multiply-looped ring structure having a hierarchical structure in which a linear structure as an element of a ring structure is made of a thinner ring structure, characterized in:
exhibiting a nature regulated by setting a number of elements in case the ring structure is made of thinner ring structures.
According to the eighteenth aspect of the invention, there is provided a multiply-looped ring structure having a hierarchical structure in which a linear structure as an element of a ring structure is made of a thinner ring structure, characterized in:
having a dimensionality regulated by setting a number of elements in case the ring structure is made of thinner ring structures.
According to the nineteenth aspect of the invention, there is provided a multiply-looped ring structure having a hierarchical structure in which a linear structure as an element of a ring structure is made of a thinner ring, having a random potential introduced therein, and at least two ring structures bonded in at least one site, characterized in:
a quantum chaos occurring therein being controlled by setting the intensity of the random potential, by setting the intensity of layer-to-layer bonding, by setting the number elements used when forming the ring structure from thinner ring structures, or by adding a magnetic impurity.
Control of the quantum chaos produced typically relies on setting a bonding force between layers. Addition of magnetic impurities contributes to a decrease of the bonding force between layers and good control of the quantum chaos.
According to the twentieth aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-looped ring structure having a hierarchical structure in which a linear structure as an element of a ring structure is made of thinner ring structures, characterized in:
at least two layers of the ring structures being bonded to each other in at least one site.
According to the twenty-first aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-looped ring structure having a hierarchical structure in which a linear structure as an element of a ring structure is made of thinner ring structures, characterized in:
the multiply-looped ring structure exhibiting a nature regulated by setting the number of elements used when the ring structure is made of thinner ring structures.
According to the twenty-second aspect of the invention, there is provided a functional material including in at least a portion thereof a multiply-loop ring structure having a hierarchical structure in which a linear structure as an element of a ring structure is made of thinner ring structures, characterized in:
the multiply-looped ring structure having a dimensionality regulated by setting a number of elements in case the ring structure is made of thinner ring structures.
In the present invention, in the multiply-complexed one-dimensional structure, the curvature used when a one-dimensional structure in the first layer, for example, is made of a thinner one-dimensional structure in the second layer lower by one layer than the first layer is set to a value different from the curvature used when a one-dimensional structure in the third layer different from the first layer is made of a thinner one-dimensional structure in the fourth layer lower by one layer than the third layer. This curvature may be set to a different value, depending on a difference in position in the one-dimensional structure of the same layer. In the multiply-twisted helix, the turn pitch used when a spiral structure in the first layer, for example, is made of a thinner spiral structure in the second layer lower by one layer than the first layer is set to a value different from the curvature used when a spiral structure in the third layer different from the first layer is made of a thinner spiral structure in the fourth layer lower by one layer than the third layer. This turn pitch may be set to a different value, depending on a difference in position in the spiral structure of the same layer. In the multiply-looped ring structure, the number of elements used when a ring structure in the first layer is made of a thinner ring structure in the second layer go lower than one layer than the first layer is set to a value different from the number of elements used when a ring structure in the third layer different by one layer from the first layer is made of a thinner ring structure in the fourth layer lower by one layer than the third layer. This number of elements may be set to a different value, depending on a difference in position in the ring structure of the same layer.
There may be fluctuation in sites where spiral structures, ring structures or one-dimensional structures bond between at least two layers. This is equivalent to introduction of randomness to sites where spiral structures, ring structures or one-dimensional structures are bonded between layers. xe2x80x9cFluctuationxe2x80x9d involves both spatial fluctuation (that can be reworded to disturbance or deviation) and temporal fluctuation. Any way is employable for introduction of fluctuation. For example, it may be introduced to appear in predetermined pitches. The fluctuation may be introduced by removing or adding bonds between at least two layers of spiral structures, ring structures or one-dimensional structures.
Curvature of the multiply-complexed one-dimensional structure, turn pitch of the multiply-twisted helix or number of elements of the multiply-looped ring structure is made variable under external control, for example. In a typical example of the multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure, the one-dimensional structure, spiral structure or ring structure is made of a linear formation essentially made of atoms or groups of atoms (clusters) as elements. To introduce the above-mentioned fluctuation into this kind of structure, there is a method of inducing random absorption or elimination (surplus bonds or lack of bonds) of molecules in the linear formation. Since such introduction of a change or fluctuation of the curvature, turn pitch of number elements can be utilized as a kind of memory function, these multiply-complexed one-dimensional structure, multiply-twisted helix and multiply-looped ring structure can be used as memory devices.
In the present invention, control of curvature in the multiply-complexed one-dimensional structure, turn pitch in the multiply-twisted helix or number of elements in the multiply-looped ring structure can bring about phase transition, especially metal-insulator phase transition or ferromagnetic phase transition. Critical value of the phase transition is regulated in accordance with the curvature, turn pitch or number of elements. This phase transition is controlled by control of bonding positions between one-dimensional structures, helical structures or ring structures of two layers. Specifically, these positions are controlled by parallel movements of these bonds. Specifically, the multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure includes, for example, metallic phase portions and insulating phase portions. The insulating phase portions can change their phase to the metallic phase because of their versatility. Critical temperature of ferromagnetic phase transition can be regulated by the degree of the above-mentioned fluctuation. Alternatively, critical temperature for ferromagnetic phase transition can be regulated by parallel movements of bonds between at least two one-dimensional structures, spiral structures or ring structures of different layers.
In a multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure, including one-dimensional structures, helical structures or ring structures of at least two different layers, which are bonded, at least, at one position, if this at least one bond itself is made in form of a linear structure, then it is possible to control various physical phenomena that take place in the structure. For example, by setting the force of the bond made in form of a linear structure, critical temperature for ferromagnetic phase transition can be regulated. Alternatively, quantum chaos that may take place can be controlled. Further, electron state (electron correlation) can be controlled thereby to control metal-insulator phase transition.
In a multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure, including one-dimensional structures, spiral structures or ring structures of at least two different layers, which are bonded, at least, at one position, if this at least one bond is made via an independent element, then it is possible to control various physical phenomena that take place in the structure. For example, by regulating critical temperature for ferromagnetic phase transition by making use of the criticality obtained by the structure, the structure can exhibit a stable physical property against minute structural fluctuations. Alternatively, control of the quantum chaos or control of metal-insulator phase transition is possible. Furthermore, it is possible to control the electron state thereby to control metal-insulator phase transition. These structures are not sensitive to structural fluctuations and exhibit pandemic physical properties, so it is easy to mass-produce a material exhibiting a constantly uniform physical property.
Features of the present aspect of the invention common to those of the fourth, 11th and 19th aspects of the invention are directly applicable to functional materials using any of the multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure. Features of the present aspect of the invention common to those of the 12th aspect of the invention are also applicable to the multiply-complexed one-dimensional structure when the helical structures are replaced by one-dimensional structures having a finite curvature, and to the multiply-looped ring structure when the helical structures are replaced by ring structures. They are also applicable to functional materials using the multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure.
According to the invention having the above-summarized configurations, by appropriately setting curvature of the multiply-complexed one-dimensional structure, spiral turn pitch of the multiply-twisted helix or number of elements in the multiply-looped ring structure, it is possible to select a desired value of spatial filling ratio, thereby modify or control dimensionality of the material and control physical properties that the material exhibit. Especially, for example, by controlling the number of nearest-neighbor elements in the multiply-complexed one-dimensional structure, multiply-twisted helix or multiply-looped ring structure, it is possible to modify phase transitional natures such as Mott-Hubbard metal-insulator phase transition or magnetic phase transition. Further, by introducing fluctuations of bonding sites between at least two one-dimensional structures, spiral structures or ring structures of different layers, that is in other words, by introducing randomness in bonding sites between one-dimensional structures, spiral structures or ring structures of different layers and controlling the intensity of the randomness, it is possible to adjust the insulation performance by inter-electron correlation for wider material designs. Furthermore, the quantum chaos can be controlled by appropriately setting the potential intensity and the bonding force between layers when introducing random potentials, by appropriately setting the curvature when one-dimensional structures in the multiply-complexed one-dimensional structure are made of thin one-dimensional structures, by appropriately setting the turn pitch when spiral structures in the multiply-twisted helix are made of thin helical structures, by appropriately setting the number of elements when ring structure in the multiply-looped ring structure are made of thin ring structures, or by addition of magnetic impurities.